Koa Butterflies on ʻIliahi Flowers

I hiked along the rim of Makua Valley where I saw dozens of koa butterflies sipping the nectar of ʻiliahi flowers.

I attended the Hawaiian Trail and Mountain Club’s 3-day Mokuleʻia Campout where backpackers hike the Kuaokoala Trail, Mokuleʻia Access Road, and the rim of Makua Valley to get to the hunter’s shelter in the Mokuleʻia Forest Reserve. The 3-day campout provides a good opportunity to look for and photograph rare native plants and animals.

On Oʻahu some of the best remaining examples of native mesic and dry forests can be found in Pahole Natural Area Reserve in the Mokuleʻia Forest Reserve. One of my favorite things to do is to visit a native sandalwood tree with unusually large droopy leaves and a trunk 18 inches in diameter — large by Oʻahu standards.

This species of ʻiliahi or sandalwood tree (Santalum freycinetianum) ʻiliahi is not endangered but is by no means common. Endemic to the Hawaiʻi, this species of sandalwood is found in drier climates in the Koʻolau and Waiʻanae Mountains. This particular ʻiliahi tree is unique for its size and girth. I have not seen many ʻiliahi trees larger that this on Oʻahu.

The tree was covered with hundreds of clusters of small pinkish-red buds. The buds in each cluster are timed to open only a handful at a time so the tree provides a stable source of nectar for months at a time.

The buds open into four petaled flowers a quarter inch in diameter which are irresistible to koa butterflies — Udara blackburni. Known as Hawaiian blues or Blackburn’s butterfly, the butterflies are about three quarters of an inch long. Koa butterflies are one of only two species of butterflies endemic to Hawaiʻi.

Koa butterflies are about three-quarters of an inch long with the upper sides of its wings blue-gray and its undersides turquoise-green. This duality gives the butterfly a different appearance depending which side you see.

The life cycle of koa butterflies are tied to koa trees (Acacia koa). Adults lay eggs on koa trees and their caterpillars feed on koa leaves.

Koa butterflies love ʻiliahi flowers. When they first land, their proboscis is curled up like a coil.

The proboscis — which the butterfly uses as a straw — is unrolled and inserted into the flower so the butterfly can sip the nectar at the bottom.

The body of the butterfly is covered with a thick coat of blue colored hairs.

Scales covering the surface of the wings look like rows of overlapping shingles on a roof.

The ʻiliahi trees and koa butterflies were so amazing to photograph that time passed quickly and soon it was time for me to move on and visit other even more rare native plants and animals. Stay tuned for the next post to see rare and endangered kahuli — Oʻahu tree snails — in the Mokuleʻia Forest Reserve!

Your website is absolutely fantastic. It is evident you have a real love and appreciation for the Hawaiian environment and all the special and unique flora and fauna of the islands. There are so many websites with people talking about hikes they have taken but so few of these bloggers seem to care or know anything about native species. Thanks so much for setting things straight!